Wearable alarm system for a prosthetic hearing implant

ABSTRACT

A prosthetic hearing implant kit is disclosed. The prosthetic hearing implant kit comprises internal components configured to be implanted in a recipient and comprises an internal coil; external components configured to be worn by the recipient and comprises an external coil adapted to be inductively coupled with said internal coil; and an alert system having a second external coil and adapted to receive an external alarm and to transmit signals to said implanted components via said external coil for providing the recipient with a corresponding alarm indication.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of 11/487,402 filed Jul. 17, 2006,which makes reference to and claims the benefit of co-pending AustralianProvisional Patent Application No. 2005903755 filed Jul. 15, 2005, eachof which is are hereby incorporated by reference herein.

BACKGROUND

1. Field of the Invention

The present invention relates generally to prosthetic hearing implantsand, more particularly, to a wearable alarm system for a prosthetichearing implant.

2. Related Art

Door bells, telephones, alarm systems (fire, intruder, smoke etc), alarmclocks, and analogous devices emit acoustic warning signals making themsuitable for people having normal hearing. People with severe orprofound hearing loss must receive a prosthetic hearing implant such asa cochlear™ prostheses (commonly referred to as cochlear™ prostheticdevices, cochlear™ implants, cochlear™ devices, and the like; simply“cochlear implants” herein), to perceive such sounds.

However, most auditory prosthetic recipients prefer to sleep withoutwearing the external components of the prosthesis due to the physicalshape, size, weight and/or the need for interconnecting cables, whichare designed for use by the recipient during normal daily activities.This renders such recipients cut off from external audio input whileasleep. This can be very inconvenient if the sound from an alarm clockis not heard or could be potentially dangerous in the event of a fire orintruder alarm not being heard.

Current warning devices for the hearing impaired mostly involve visualnotification such as a flashing light to alert the person to the phoneringing, people at the door, or alarms such as smoke alarms. Such avisual alarm is obviously not adequate when asleep. Alarms for sleeping,hearing impaired people exist using vibration, either of the bed orpillow to wake the person. Such alarms can be activated by phone, babyalarms, smoke alarms etc. However, such devices are cumbersome, usuallyrequire a power source (with battery as back up only) and are notreadily transportable.

Other situations may arise which require the removal of the externaldevice, such as when recipients need to wear a closely fitting helmet. Ahelmet may need to be worn when riding a bike, motorcycle, when skiing,or even on a building site. Removal of the external device can bedangerous in such situations as the recipients are not able to hearwarning signals that alert people in the surrounding area to danger.

SUMMARY

In one aspect of the invention, a prosthetic hearing implant kit isdisclosed. The prosthetic hearing implant kit comprises internalcomponents configured to be implanted in a recipient and comprises aninternal coil; external components configured to be worn by therecipient and comprises an external coil adapted to be inductivelycoupled with said internal coil; and an alert system having a secondexternal coil and adapted to receive an external alarm and to transmitsignals to said implanted components via said second external coil forproviding the recipient with a corresponding alarm indication.

In another aspect of the invention, an alert system for use in aprosthetic hearing implant is disclosed. The alert system for use in aprosthetic hearing implant comprises an event detection modulecomprising at least one microphone and a transmitter configured totransmit a signal representative of received audio signals; and awearable alarm module configured to analyze one or more characteristicsof said representative signal, and to invoke said prosthetic hearingimplant to generate an alarm indication when said representative signalrepresents a received audio signal constituting an alarm event.

In a further aspect of the invention, a method of communicating anexternal alarm to the recipient of a prosthetic hearing implant isdisclosed. The method of communicating an external alarm to therecipient of a prosthetic hearing implant comprises receiving at anevent detection module audio signals; transmitting to a wearable alarmmodule signals representative of said received audio signals;determining by said wearable alarm module whether said receipt of saidaudio signals constitutes an alarm condition; and controlling theprosthetic hearing implant to provide the recipient with an alarmindication when said audio signals constitute an alarm condition.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrative embodiments of the present invention will be described withreference to the accompanying drawings, in which:

FIG. 1 is a schematic block diagram of an exemplary cochlear implantwith which aspects of the present invention may be implemented;

FIG. 2 is a schematic block diagram of one embodiment of a cochlearimplant alert system showing the alert system integrated into a cochlearimplant such as the cochlear implant illustrated in FIG. 1;

FIG. 3A is a perspective view of one embodiment of a cochlear implantalarm apparatus shown in its operational position so as to interoperatewith implanted components of the cochlear implant illustrated in FIG.1A;

FIG. 3B is a perspective view of another embodiment of a cochlearimplant alarm apparatus shown in its operational position so as tointeroperate with implanted components of the cochlear implantillustrated in FIG. 1A;

FIG. 4 is a schematic block diagram of the wearable alarm module shownin FIG. 2 in accordance with one embodiment of the present invention;

FIG. 5A is the top view of the alarm module showing the layout of themajor components and functional modules in accordance with oneembodiment of the present invention;

FIG. 5B is a side view of the alarm module of FIG. 5A in accordance withone embodiment of the present invention;

FIG. 5C is a bottom view of the alarm module of FIG. 5A in accordancewith one embodiment of the present invention;

FIG. 6A is a bottom and side view of the one-piece device showing theapplication of an elastomeric coating to the bottom surface inaccordance with a further embodiment of the present invention;

FIG. 6B is a bottom and side view of the thin flexible coil assemblyshowing the application of an elastomeric coating over all surfaces inaccordance with a further embodiment of the present invention;

FIG. 6C is a conceptual view of the receiver module (FM receiver/controlunit) for use with the flexible coil assembly in accordance with afurther embodiment of the present invention;

FIG. 7A is a side view of a transmission coil with an elastomericcoating in accordance with a further embodiment of the presentinvention;

FIG. 7B is a bottom view of the transmission coil of FIG. 7A inaccordance with a further embodiment of the present invention;

FIG. 8A is a cross-sectional plan view of an alert system transmissioncoil in accordance with one embodiment of the present invention;

FIG. 8B is a cross-sectional side view of the transmission coilillustrated in FIG. 8A;

FIG. 8C is a top cross-sectional view of an alert system transmissioncoil in accordance with another embodiment of the present invention;

FIG. 8D is a side view of a side view of an encapsulated coil inaccordance with a further embodiment of the present invention; and

FIG. 9 is a cross-sectional view of the transmission coil illustrated inFIGS. 8A and 8B fixedly secured to an interior surface of a helmet.

DETAILED DESCRIPTION Introduction

Aspects of the present invention provide an alert system for animplanted hearing prosthesis recipient. The alert system is worn by therecipient in place or in addition to the external components of thehearing prosthesis. Upon receipt of a predefined external alarm thealert system transmits signals which are received by an implantedhearing prosthesis as an alarm indication. The present invention may beutilized, for example, under conditions where it may not be practicalfor recipients to wear their normal speech processor, such as while inbed sleeping.

In a broad form, the present invention provides an alarm system forcommunicating an alarm to an implanted hearing prosthesis recipient.

In one aspect, the alarm system is adapted to receive an external alarmand includes means to transmit alarm signals adapted to be detected andreceived by an implanted hearing prosthesis as an alarm indication, thearrangement being such that when an external alarm is received, thealert system transmits an alarm signal.

In another aspect, the present invention provides a method ofcommunicating an external alarm to the recipient of an implanted hearingprosthesis, including: providing an alarm device adapted to receive anexternal alarm; upon receiving an external alarm, transmitting saidexternal alarm to said implanted hearing prosthesis as an alarm signal.The alarm device may include an FM receiver, alarm detection,encoder/transmitter functions, an LCD display, user interface, powersupply and alarm clock functions. In one embodiment, the alarm deviceincludes only the FM receiver, alarm detection and encoder/transmitterfunctions. The alarm clock functions are removed and the push buttonuser interface is simplified to just an on/off switch.

The alert system may be configured to respond to any of its alarm inputsand to transmit an encoded alarm stimulus sequence to the cochlearimplant to alert the recipient.

The alert system may be powered by battery or other power source such asa capacitor. The alert system may operate with very low standby poweruntil an alarm condition occurs, at which time it sends short durationpower and data signals to the implant. In this way, the powerrequirements, physical size and weight of the device can be minimized.

The alert device may be made up from a transmitter module and a receivermodule. Preferably, the receiver module includes an FM wireless receiverlinked to a remote FM wireless microphone that picks up environmentalsounds and specifically, sounds that the cochlear implant recipientneeds to be alerted about. The alert device could then be programmed torespond only to sustained sounds of sufficient loudness to be classifiedas alarms. Such sounds could include an alarm clock, door bell,telephone or fire or intruder alarm. The alert system may also beconfigured to respond to a baby monitor if a wireless microphone wasplaced close to the loudspeaker of the monitor. The FM wirelessmicrophone system is preferably a standard commercially available systemof the type typically used by hearing impaired persons to augment theirhearing prosthesis. FM wireless receivers systems are now available aslow power, single chip devices, facilitating easy integration intocustom electronic devices. By making it compatible with existing FMsystems the alert device can become more affordable and easier to use.

In one embodiment, the alert system may be easily and securely attachedwhile being relatively unobtrusive to the wearer. Present commerciallyavailable alarm monitoring/alerting systems are relatively large andbulky and use vibratory “bed shakers” as the alerting means. Embodimentsof the present invention require only a small head-worn device inaddition to the wireless microphone that many recipients will already beusing.

In one embodiment, the wearable alarm device is entirely self-containedin a single head worn assembly and operates in conjunction with acommercially available wireless microphone. It may include a digitalalarm clock, LCD display, programmable alarm selection and aprogrammable power and data encoder that allows presetting the type ofelectrical stimulus that is sent to the implant to represent the alarmsound sounds. In this instance, the holding means may be a combinationof magnetic forces and a soft elastomeric layer on the bottom surface ofthe coil to securely locate the device on the head.

Alternatively, the transmitter module that couples to the prosthesis isa separate component and is made of very thin and flexible materialallowing it to be worn unobtrusively under a light weight headband. Thiscoil configuration would typically not use a magnet for attachment sincethe magnet is a relatively thick and rigid component. In thisembodiment, the non-slip coating could be used advantageously on bothbottom and top surfaces of the coil to improve its fixation to the headand headband. This part of the alarm device may be fixed to the headbandby other means such as a pocket, adhesive, clip or Velcro. The otherpart of the alarm device, the receiver module, in this case an FMreceiver and control functions, are then built into a separate modulethat can be attached to the front of the headband via a clip or pocketsewn into the headband, etc. The coil may be connected to the controlunit by a short, light-weight cable or may even be located separately tothe transmitter module. Such a thin and flexible coil also hasapplication for hearing prosthesis recipients who need to wear closefitting helmets for sports and cycling, and can be used in conjunctionwith the recipient's regular speech processor.

Thus recipients can have the choice of either a single integratedpackage attached via the magnet and no-slip surface or a headbandmounted system or a combination. The present invention accordinglyallows people with a hearing prosthesis to conveniently be alerted toalarms while sleeping or when they are without their external speechprocessor. This provides a significant advantage to the hearingprosthesis recipient over existing alternatives.

Exemplary Cochlear Implant

In another embodiment, the alert system may be easily and securelyattached while being relatively unobtrusive to the wearer. Presentcommercially available alarm FIG. 1 is a perspective view of anexemplary cochlear implant 120 in which embodiments of the presentinvention may be advantageously implemented. In fully functional humanhearing anatomy, outer ear 101 comprises an auricle 105 and an ear canal106. A sound wave or acoustic pressure 107 is collected by auricle 105and channeled into and through ear canal 106. Disposed across the distalend of ear canal 106 is a tympanic membrane 104 which vibrates inresponse to acoustic wave 107. This vibration is coupled to oval windowor fenestra ovalis 110 through three bones of middle ear 102,collectively referred to as the ossicles 111 and comprising the malleus112, the incus 113 and the stapes 114. Bones 112, 113 and 114 of middleear 102 serve to filter and amplify acoustic wave 107, causing ovalwindow 110 to articulate, or vibrate. Such vibration sets up waves offluid motion within cochlea 115. Such fluid motion, in turn, activatestiny hair cells (not shown) that line the inside of cochlea 115.Activation of the hair cells causes appropriate nerve impulses to betransferred through the spiral ganglion cells and auditory nerve 116 tothe brain (not shown), where they are perceived as sound. In deafpersons, there is an absence or destruction of the hair cells. Acochlear implant 120 is utilized to directly stimulate the ganglioncells to provide a hearing sensation to the recipient.

FIG. 1 also shows how a cochlear implant 120 is positioned in relationto outer ear 101, middle ear 102 and inner ear 103. Cochlear implant 120comprises external component assembly 122 which is directly orindirectly attached to the body of the recipient, and an internalcomponent assembly 124 which is temporarily or permanently implanted inthe recipient. External assembly 122 comprises several componentsincluding a plurality of audio sensors spatially arranged on externalcomponents 122 of cochlear implant 120 for detecting sound. The spatialarrangement of the plurality of audio sensors is described in greaterdetail below.

Sound processor 126 is an directional sound processor configured togenerate coded stimulation control signals representing sound detectedby the plurality of audio sensors from a desired direction. These codedsignals are then provided to an external transmitter unit 128. In theembodiment shown in FIG. 1, sound processor 126 is a behind the ear(BTE) sound processing unit. The BTE is constructed and arranged so thatit can fit behind the outer ear 101 of a recipient. BTE may include apower source to power all elements of the cochlear implant, such as theexternal coil. In certain embodiments, the power source may bephysically disconnected from the BTE, thereby causing the BTE todiscontinue operation. Furthermore, in other embodiments, accessoriescan be connected to the BTE to add additional functionality.

It would be appreciated by one of ordinary skill in the art that soundprocessor 126 may also comprise a body-worn sound processor, a modularsound processor or a sound processor headset. Details of the soundprocessing performed in sound processor 126 in accordance withembodiments of the present invention are discussed below.

External transmitter unit 128 comprises an external coil 130 and,preferably, a magnet (not shown) secured directly or indirectly inexternal coil 130. External transmitter unit 128 is configured totransmit the coded signals from sound processor 126, along with powerfrom a power source 129 such as a battery to internal components 124through tissue 152.

Internal components 124 comprise an internal receiver unit 132 having aninternal coil (not shown) that receives and transmits power and codedsignals received from external assembly 122 to a stimulator unit 134 toapply the coded signal to cochlear 115 via an implanted electrodeassembly 140. Electrode assembly 140 enters cochlea 115 at cochleostomyregion 142 and has one or more electrodes 150 positioned to besubstantially aligned with portions of tonotopically-mapped cochlea 115.Signals generated by stimulator unit 134 are typically applied by anarray 144 of electrodes 150 to cochlea 115, thereby stimulating auditorynerve 116.

FIG. 2 is a functional block diagram of one embodiment of a cochlearimplant alert system 200 of the present invention. As noted, alertsystem 200 generally comprises an event detection module 202 and awearable alarm module 204, as noted above.

In one embodiment, event detection module 202 is an FM wireless systemthat comprises sensitive microphone(s) 206 configured for wide-angle,normal or directional sound pick up. This allows event detection module202 to be either placed centrally in a room such that it picks up allsounds (for example, fire or intruder alarm, telephone, door bell, etc),or alternatively placed next to an alarm or monitoring device to enablepreferential detection of acoustic outputs from specific devices (forexample, clock radio alarm, baby monitor, mobile phone etc.). Eventdetection module 202 transmits a signal 208 in response to the presenceof an audio signal. In the embodiment shown in FIG. 2A, signal 208 is awireless signal such as an RF signal.

Wearable alarm module 204 receives signal 208 and determines whether analarm event has been detected. This is determined by analyzing one ormore characteristics of the received signal, such as amplitude,frequency, duration, etc. Alternatively, more sophisticated signalanalysis can be performed on the received FM signal to select specificsounds, for example, via an integrated digital signal processor (DSP).

When an alarm event is detected, a transmission to internal components124 of cochlear implant 120 occurs. The transmission may comprise apredefined burst of encoded RF energy.

FIGS. 3A and 3B are perspective views of alternative embodiments of thewearable alarm module shown in its operational position on a recipient.As noted, when in the illustrated position, the wearable alarm moduleinteroperates with implanted components 124 of cochlear implant 100.

Wearable alarm module 204 comprises a variety of components describedbelow, including a transmitter coil 304 to be inductively coupled toimplanted coil 132 (FIG. 1). The embodiment of wearable alarm module 204illustrated in FIG. 3A, referred to as wearable alarm generation module300, is a single integrated unit held in place on the recipient byutilizing rare earth magnets. One magnet 302 is located in wearablealarm module 300 while the other is located in cochlear implantedstimulator/receiver unit 134 (FIG. 1). In one embodiment, such magnetswill hold coil 304 in position for an axial separation with internalcoil 132 of at least 10 mm and for lateral offsets of at least 6 mm.

The embodiment of alarm module 204 illustrated in FIG. 3B, referred toas alarm generation module 350, comprises two separate components: aseparate thin, flexible coil 352 connected via a cable 354 to a controlunit 356. These components are removably secured to a light-weight headband 358. Rather than the fully integrated system of FIG. 3A, separatecoil 352 may be made very thin and flexible so that it conforms to theshape of the recipient's head. This allows it to be held in positionunder unobtrusive, light-weight head band 358 that may be comfortablyworn during sleep. People readily adapt to wearing such things at nightand a head band is far less obtrusive than say a sleep-apnea mask.

Preferably, thin coil 352 does not include a magnet since this increasesits thickness and weight. However, the application of a non-slipelastomeric coating to at least the bottom surface of integrated device300 would be advantageous to ensure coil 352 remains in position.

Another benefit of a thin flexible coil 352 compared to a moreconventional rigid coil is that it inherently makes closer contact withthe recipient's head. It can also be made somewhat larger in diameterwithout increasing the bulk of the coil. Both of these attributes may beused to improve the degree of coupling to implant receiver coil 132 andimproving the tolerance of the system to coil misalignment. In thisembodiment, the remaining components of wearable alarm device 350 aredisposed in a separate case that can be made quite small withoutconsideration to the size of the integrated coil. Alternatively, a largeflexible coil may be used with a small control box. FM receiver/controlunit 356 is attached to headband 358 via a clip, Velcro, or sewn inpocket or any other suitable means. It is not necessary to stabilize itsposition relative to the recipient's head. Short cable 354 connects coil352 to control unit 356. In embodiments in which there is an electricalconnector to coil 302/352 such connector is preferably located away fromthe coil itself to avoid the bulk of a connector. This can readily beachieved by fabricating leads 354 to coil 352 using the same flex-PCBprocess that is used to make the coil 352. The dimensions of coil 352are approximately 25 mm to 40 mm in diameter and the integrated leadwould be approximately 50 mm to 100 mm in length. It should beappreciated that other dimensions are possible given the particularapplication.

FIG. 4 is a schematic block diagram of one embodiment of alarm module204. Wearable alarm module 204 receives signal 208 at an FM receivermodule 410. FM receiver module 410 demodulates signal 208 and providesan audio signal 412 to an A/D input of a microcontroller 440.Microcontroller 440 monitors audio signal 412 to detect a signal thatexceeds preset energy thresholds, i.e. a combination of signal amplitudeand duration. Alternatively, more sophisticated signal analysis can beperformed on the received FM signal to select specific sounds, forexample, via an integrated digital signal processor (DSP).

When a suprathreshold signal is detected, microcontroller 440 sendscontrol data 414 to the data-encoder and transmitter module 450. Thisresults in the transmission to internal components 124 of cochlearimplant 120 of a predefined burst of encoded RF energy via transmittercoil 480. As with external coil 130, transmission coil 480 isinductively coupled to internal coil 132 of cochlear implant 120 whenwearable alarm module 204 is properly positioned on the recipient'shead. Cochlear implant 100 extracts both power and data from theinductively coupled energy, and outputs the stimulus sequence encodedtherein.

The preceding description applies to a cochlear implant that receivesboth power and data from an external device. Note that alternativecochlear implant architectures include an implanted energy source and/ora stimulus sequence controller. In this case, alert system 200 may sendonly a data signal to the implanted components of the cochlear implantsufficient to cause it to output a predefined alerting sequence.However, for the purpose of clarification of the present invention, itsoperation is described assuming a conventional externally poweredcochlear implant.

In its simplest form, the predefined data sequence transmitted tointernal components 124 is a constant amplitude stimulus sequencedirected to one of the active electrodes. Alternatively, it could be asequence of pulses applied sequentially to a group of predefinedelectrodes. The object is to create a sound capable of arousing therecipient from the sleeping state. It may be desirable to steadilyincrease the amplitude of the stimuli over a series of bursts to avoidstartling the person from their sleeping state.

Each cochlear implant recipient has unique electrical stimulationparameters so it is necessary to set stimulus levels to suit eachrecipient of the device. These parameters are typically set up at acochlear implant clinic during a routine fitting session.Advantageously, alarm system 200 may be set up via the regularprogramming system and uses the same serial communications port used forprogramming recipients' speech processors. The recipient is able toselect from a range of predefined alarm tones and the stimulus leveldefaults to a value based on the recipient's “comfort” level, which isknown from parameters acquired during the fitting of the speechprocessor. The default value can then be adjusted up or down asnecessary, or the user may have access to the loudness control via theuser interface 230 if this is provided. After programming, alarm system200 becomes personalized to a specific recipient.

It is desirable that alert system 200 is as small and light weight aspracticable so that it is minimally obtrusive to the recipient. Althoughcochlear implants have improved significantly over time and withadvances in low power electronics, power consumption remains an issuedue to the inherent inefficiency of the inductively coupled RFpower/data link. State of the art cochlear implants use high energydensity primary cells such as Zinc/air or rechargeable Lithium Ion orNickel Metal Hydride secondary cells. These cells are small enough to beincorporated into speech processor configurations that can be wornbehind the ear (BTE). These devices are very large by hearing aidstandards, but users accept this size in preference to having an evenlarger body-worn device with the associated interconnecting cables tothe ear-level components (for example, the microphone and coil). It hasnot been practical to build a multi-channel cochlear implant speechprocessor entirely into a self supporting on-the-head (OTH) device dueto the size and weight of the batteries that would provide sufficientpower to maintain continuous operations for a reasonably acceptableperiod of time.

However, alert system 200 typically operates in a low power standby modeand draws high power for only relatively short periods of time inresponse to detection of an alarm condition. For example, a typicalcochlear implant draws power of the order of 50 mW while processing andtransmitting normal environmental sounds and speech to the implant. Thisis not the maximum power consumption but is based on a transmission dutycycle of approximately 50%. A power source would need to have a capacityof 400 mWhr to support such a system for 8 hours. This compares to alertsystem 200 for which the high power duty cycle would be perhaps 1 minutein 8 hours, that is, approx 0.2%, for the wake-up alarm application.Low-power control electronics and FM receiver module 210 would consumeapprox 1.5 mA or 5 mW from a Lithium battery 470 during the standbystate. This translates to approximately 40 mWhr for 8 hours of operationor 10% of a typical cochlear implant. With battery 470 being the largestcomponent of alert system 200), such a substantial reduction in powerrequirement makes it possible to design a thin and light-weight device.

In one embodiment of the present invention, wearable alarm module 204further comprises a real-time clock/alarm 460 and an LCD 420. Thisallows alert system 200 to be used in a limited way, for example,autonomous alarm clock wake-up mode only, independent of event detectionmodule 202. For this mode of operation it is necessary to set up theoperating parameters, for example, set time, set alarm clock, alarmon/off, external alarm detection (FM receiver) on/off, alarm soundselect, alarm loudness adjust. This is achieved via a user interface(UI) having several pushbuttons that allow the recipient to configurethe device. Whilst it is possible to provide access to all of thesefunctions via user interface 430, it may be preferable that theseparameters are configured by the audiologist/clinician via theprogramming system, as described above.

FIGS. 5A-5C are top, side and bottom views, respectively, of oneembodiment of alarm device 200, referred to herein as alarm device 500,showing the physical layout of the major components of one embodiment ofthe device. In this illustrative embodiment, the following primarycomponents are shown: LCD display 420, user interface 430, battery 470and an electronics module 506. In this embodiment, electronics module502 comprises clock module 460, microcontroller 440, FM receiver module410, and data encoder/transmitter-driver module 450.

The side and bottom views of FIGS. 5B and 5C show the layout of anembodiment of transmit coil 510. In this embodiment, transmit coil 510is a spirally wound flat PCB coil. As can be seen, the arrangement ofthe elements shown in FIGS. 5A-5C minimizes the size of the wearablealarm module 500 of the system.

In addition to the desire for a small and light weight wearable alarmmodule that is minimally obtrusive to the wearer, alarm modules of thepresent invention are preferably reliably and securely held on arecipient's head so that they remains relatively fixed in position overan implanted receiver coil. FIGS. 3A and 3B described above are just twomethods of holding an alarm module in place, but other fixation meansare possible.

FIG. 6A is a side and bottom view of alert system 300 illustrated inFIG. 3A. Similarly, FIG. 6B is a side and bottom view of coil 352 andlead 354 of alert system 350 illustrated in FIG. 3B. In the embodimentillustrated in FIG. 6B, coil 352 and lead 354 are coated with anelastomeric coating material to impart ‘stickiness’ and durability tothe coil. An in-line connector 602 is located at the end of lead 354 tofacilitate connection to FM receiver/control unit 356 (FIG. 6C).

In the embodiment illustrated in FIG. 6A an elastomeric coating 606 hasbeen applied to the bottom surface of alert device 300. The elastomericmaterial can include dimples, protrusions and the like, to improveretention onto the recipient's head by way of increasing friction atthis interface. The elastomeric coating 606 may increase the distance ofthe coil from the head by approximately 1 mm.

This magnetic fixation scheme can be significantly augmented by theapplication of a non-slip elastomeric coating 606 on the bottom surfaceof the coil, preventing small disturbances, such as rolling the head ona pillow, from dislodging the coil.

By improving the retention of the transmitting coil on the recipient'shead, the magnetic holding force can be reduced, thus reducing theweight of the coil by using smaller magnets. This also provides animproved comfort level for the recipient.

A variety of elastomeric coating materials are available and the choiceof material depends on the final design parameters of the device(compatibility with the substrate, durability, color, feel etc.). Thefollowing materials would be suitable: Kraton TPC having a hardness inthe range of Shore A 15 to Shore A 50; Santoprene TPV having a hardnessin the range of Shore A 30 to Shore A 50′ Nitrile rubber NRB having ahardness in the range of Shore A 30 to Shore A 50; and Silicone Rubberhaving a hardness in the range of Shore A 30 to Shore A 50.

Some recipients may find it preferable to use a head band in conjunctionwith the one piece magnetically attached device. Alternatively the coilcould be built into the headband.

It is noted that the elastomeric coating can also be applied to atraditional transmission coil, as shown in FIGS. 7A and 7B. FIG. 7A is aside view and FIG. 7B is a bottom view of an embodiment of external coil130 illustrated in FIG. 1, referred to herein as external coil 700.External coil 700 has an elastomeric coating 702 applied to the surfacethat abuts a recipient's skull. In this embodiment, elastomeric coating702 is applied around the perimeter of the entire device. It should beappreciated, however, that elastomeric coating 702 may be appliedcontiguously or non-contiguously around a portion or the entireperiphery of the device surface.

Embodiments of a thin transmission coil is described next below withreference to FIGS. 8A through 8D. FIG. 8A is a cross-sectional plan viewof an alert system transmission coil in accordance with one embodimentof the present invention. FIG. 8B is a cross-sectional side view of thetransmission coil illustrated in FIG. 8A. FIG. 8C is a topcross-sectional view of an alert system transmission coil in accordancewith another embodiment of the present invention. FIG. 8D is a side viewof a side view of an encapsulated coil in accordance with a furtherembodiment of the present invention.

In FIGS. 8A and 8B one embodiment of a thin transmission coil 800 isillustrated. Transmission coil 800 is similar to the transmission coilembodiments described above with reference to FIGS. 6A and 6B.

Thin transmission coil 800 comprises a conductive coil 810 disposedbetween one or more layers 825 of an insulating carrier 820. In theembodiment illustrated in FIG. 8B, there are three (3) insulating layers825 defining two conductor layers 815. In one embodiment, conductorlayers 815 may be formed of copper and approximately 0.1 mm thick. Inthe same or other embodiment, insulating layers 825 are formed of, forexample, polyimide, and are approximately 0.1 mm thick. The totalthickness of the illustrative embodiment of coil 800 is approximately0.5 mm. It should be appreciated that conductor layers 815 may have adifferent thickness and need not be of consistent thickness. Similarly,it should be appreciated that insulating layers 825 may have a differentthickness and need not be of consistent thickness.

Thin transmission coil 800 may be implemented for use with a tightfitting headgear, such as ski, cycle and motorbike helmets. Such atransmission coil 800 may be manufactured using standard PCB fabricationtechniques, which are well-known to those of ordinary skill in the art.In one embodiment, transmission coil 800 is approximately 30 mm indiameter, although transmission coil 800 may have any dimensionsappropriate for the particular application.

In FIG. 8C, an embodiment of an active transmission coil 850 isillustrated. Active transmission coil 850 comprises a conductive coil852 disposed between one or more layers of an insulating carrier 854,and surface mount components 860. Surface mount components 860 areencapsulated in an epoxy or other suitable non-electrically conductivematerial. In one embodiment, surface mount components 860 addsapproximately 0.8 mm to the total thickness of transmission coil 850.Further, either version of transmission coil 800, 850 may be overmoldedwith an elastomer. For example, FIG. 8D is a cross-sectional side viewof one embodiment of transmission coil 800 illustrated in FIG. 8A, forexample santoprene, which adds approximately 0.5 mm to the thickness.

FIG. 9 is a cross-sectional view of transmission coil 800 positionedinside a helmet 900. Helmet 900 comprises a rigid cover 910 over ashock-absorbing material 920. Hitherto, while “compression” helmetsoffer the most protection, the tightness of the fit tends to dislodgeconventional transmitter coils off the recipient's head every time thehelmet is worn. Further, it is not desirable to alter the padding ofsuch helmets to accommodate the coil, as this usually voids the warrantyof the helmet.

In the embodiment shown in FIG. 9, an exemplary transmission coil of thepresent invention, such as transmission coil 800, is shown positionedbetween shock-absorbing material 920 of helmet 900 and the head 930 ofthe recipient. In this embodiment, transmission coil 800 is a flexiblePCB as descried above with reference to FIGS. 8A and 8B, with a flexibleovermolding 840 as described above with reference to FIG. 8D. This makescoil 800 flexible and allows a better fit between head 930 and helmet900. Moreover, this advantageously ensures there is no danger of coil800 causing injury during an impact to helmet 900.

A thickness less than 2 mm is achievable, particularly given that thereis no requirement for a retaining magnetic, which is usually thethickest part of a conventional transmission coil. Preferably, connectorplug 830 is placed remote from the coil 800 attached by a short lengthof cable.

Transmission coil 800 may be fixed in position to the inside of theprotective headgear 900 as shown in FIG. 9 by, for example, glue 895. Asone of ordinary skill in the art would appreciate, fixation means 895may be, for example, Velcro, stitching, and the like in alternativeembodiments of the present invention. The thin coil option is lessexpensive to manufacture than current transmission coils. Hence if morethan one helmet was used for different sports, a different coil 800 maybe supplied for each helmet 900.

Although the present invention has been principally described withreference to a cochlear implant, it will be appreciated that thisconstruction can readily be applied to ABIs, other medical devices wherea coil is implanted in the head e.g. vision systems, deep brainstimulation (e.g. for Parkinsons treatment), Middle ear implants (DACS),or other prosthetic hearing implant now or later developed.

Throughout this specification the word “comprise”, or variations such as“comprises” or “comprising”, will be understood to imply the inclusionof a stated element, integer or step, or group of elements, integers orsteps, but not the exclusion of any other element, integer or step, orgroup of elements, integers or steps.

It will be appreciated by persons skilled in the art that numerousvariations and/or modifications may be made to the invention as shown inthe specific embodiments without departing from the spirit or scope ofthe invention as broadly described. For example, the coil described incombination with a headband or helmet could also be used by a cochlearimplant recipient who has had the implant magnet removed. Removal of theimplant magnet is a feature offered by some cochlear implants tofacilitate MRI scans. The present embodiments are, therefore, to beconsidered in all respects as illustrative and not restrictive.

Any discussion of documents, acts, materials, devices, articles or thelike which has been included in the present specification is solely forthe purpose of providing a context for the present invention. It is notto be taken as an admission that any of these matters form part of theprior art or were common general knowledge in the field relevant to thepresent invention as it existed before the priority date of each claimof this application.

1. An alert system for use in a prosthetic hearing implant comprising:an event detection module comprising at least one microphone and atransmitter configured to transmit a signal representative of receivedaudio signals; and a wearable alarm module configured to receive andanalyze one or more characteristics of the representative signal, and totransmit an alarm signal to an implanted component of the prosthetichearing implant to generate an alarm indication when, based on theanalysis, the representative signal represents a received audio signalconstituting an alarm event.
 2. The alert system of claim 1, wherein theone or more characteristics comprise one or more of the group consistingof amplitude, frequency, and duration.
 3. The alert system of claim 1,wherein the at least one microphone is configured for wide-angle, normalor directional sound pick up.
 4. The alert system of claim 1, whereinthe transmitter of the event detection module comprises an FM wirelesstransmitter.
 5. The alert system of claim 1, wherein the wearable alarmmodule is configured to transmit alarm signals of a limited number ofpredetermined types.
 6. The alert system of claim 1, wherein the alarmsignal comprises a specific stimulation signal for the prosthetichearing implant.
 7. The alert system of claim 6, wherein the wearablealarm module is configured to transmit the alarm signal as a predefineddata sequence.
 8. The alert system of claim 7, wherein the alert systemis adapted for use with a cochlear implant, and the alarm signalcorresponds to any one of an instruction to apply a constant amplitudestimulus sequence to an electrode, an instruction to sequentially applya sequence of pulses to a group of predefined electrodes, or aninstruction to apply a sequence stimulation with a steady increase inthe amplitude of the stimulation to at least one electrode.
 9. The alertsystem of claim 1, wherein received audio signal is an ambient soundsignal.
 10. The alert system of claim 1, wherein the received audiosignal is selected from the group comprising one or more of a phonering, an alarm clock, a smoke alarm, a doorbell, an intruder alarm, ababy monitor, or a sound having greater than a predetermined level. 11.The alert system of claim 1, wherein the event detection module isconfigured to transmit the signal representative of the received audiosignal by electrical, electronic or radio means.
 12. The alert system ofclaim 1, wherein the wearable alarm module is configured to be removablyheld externally adjacent the prosthetic hearing implant.
 13. The alertsystem of claim 1, wherein the wearable alarm module comprises: a helmetadapted to be worn on the recipient's head, the helmet comprising arigid cover over a shock-absorbing material; and a transmission coilpositioned inside the helmet and configured to transmit the alarm signalto the implanted component of the prosthetic hearing implant.
 14. Thealert system of claim 13, wherein the transmission coil is positionedbetween the shock-absorbing material of the helmet and the recipient'shead when the helmet is worn on the recipient's head.
 15. The alertsystem of claim 14, wherein the transmission coil is a flexible printedcircuit board.
 16. The alert system of claim 15, wherein thetransmission coil further comprises: a flexible overmolding secured tothe surface of the flexible printed circuit board.
 17. The alert systemof claim 13, wherein the transmission coil is positioned between theshock-absorbing material and the rigid cover of the helmet.
 18. Thealert system of claim 1, further comprising: a protective headgearadapted to be worn on the head of the recipient; and wherein thetransmission coil is fixed to the inside of the protective headgear.